


9.8 meters per second squared (baby, you're my gravitational constant)

by Lys ap Adin (lysapadin)



Category: Voltron: Legendary Defender
Genre: M/M, Season/Series 02, Smut
Language: English
Status: Completed
Published: 2018-03-04
Updated: 2018-03-04
Packaged: 2019-03-27 04:38:47
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 3,587
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/13873308
Author URL: https://archiveofourown.org/users/lysapadin/pseuds/Lys%20ap%20Adin
Summary: Keith has been holding out on him.Keith has been wary for as long as Shiro has known him-wary of other people and always watchful. He hangs back and takes his cues from what he sees other people doing. Not that he conforms, anything but that, since half the time the cues he takes consist ofthis makes no sense, I'm not doing it, but there's a lot of things he just doesn't seem to know how to take, or doesn't trust himself to know how to handle, without checking his instincts against the behavior of others.





	9.8 meters per second squared (baby, you're my gravitational constant)

**Author's Note:**

> Adult for porn. 3580 words, set in the middle of season 2. This one goes out to @arahir, who is an inspiration to us all.

Keith has been wary for as long as Shiro has known him—wary of other people and always watchful. He hangs back and takes his cues from what he sees other people doing. Not that he conforms, anything but that, since half the time the cues he takes consist of _this makes no sense, I'm not doing it_ , but there's a lot of things he just doesn't seem to know how to take, or doesn't trust himself to know how to handle, without checking his instincts against the behavior of others.

Shiro always figured it had to do with how Keith grew up, not that Keith has ever told him the full story. All Shiro knows is the bits and pieces that Keith lets slip, sometimes deliberately and most of the time not, that he's pieced together. Keith grew up in the system, got shuffled around a lot, so a lot of what he knows (doesn't know) is partial, disjointed, the product of an incoherent childhood. That's just how Keith is, as much a part of him as the color of his eyes or the shape of his hands. 

It's not until after Voltron—until the Blade of Marmora—that Shiro realizes there's another reason that Keith watches everyone else so carefully, that there's a reason for the contrast between the slightness of his frame and the strength it conceals. But then, even Sam Holt had figured alien species would be found at the edge of the solar system. Not even he would have thought to look under his own nose, so Shiro suppose he can be forgiven for not having seen it sooner.

Keith relaxes—that's the best way Shiro can explain it, at least after he gets over the surprise of it when he and Keith are sparring and Keith throws him across the room without even a grunt of effort.

Shiro picks himself up after the first moment of disorientation passes; Keith is still on the other side of the room, poised on the balls of his feet, wearing the same look on his face that he had the first time he'd been the one to sit at Shiro's table in the mess without being invited. 

Shiro rolls his shoulders and puts his surprise to the side for later. "You've been holding out on me," he notes. "What else you got?" 

Every last inevitable bruise he's going to walk away with is worth it just for the fragile edge of relief in Keith's answering smile. "Try me and find out."

"All right," Shiro says and closes with him again.

In retrospect, Shiro thinks as Keith comes in under his reach and tosses him over his shoulder, perhaps he should have asked himself just how Keith had managed to hold his own against so many Blades all by himself.

He tucks himself into a roll and uses his momentum to come up on his feet; Keith catches the kick over his forearm. Shiro _knows_ he's used that move to knock Keith off his balance before, but Keith doesn't budge this time, not unless Shiro wants to count the way he lets Shiro's boot slide off his arm so he can catch him by the ankle and flip him again. Shiro turns it into a handspring and comes up ready.

Keith is still holding back, though, hasn't taken advantage of the opening to press his advantage. It's not like him to hesitate, but Shiro settles into guard anyway and watches him—oh. Keith is making sure this isn't too much. Of course he is.

" _Really_ holding out on me," Shiro says at the same time he moves. 

This is only sparring, an hour stolen away from their other duties, an hour to get Keith away from the princess' chilly silences and Coran's own awkward glances, from Pidge and Hunk's curiosity and Lance's… Lance's _everything_. It's only sparring, something casual, but for once… for once Shiro allows that fact to recede to the back of his mind and goes for Keith like he means it. 

He catches a glimpse of Keith's eyes, gone wide, before Keith whirls out of his way, dropping low to spin his foot around, trying to knock Shiro off his feet. He's always liked to go low, taking advantage of his smaller frame, so Shiro is expecting that, is there to catch Keith's heel against his Galra palm. What he isn't expecting is for Keith to flow into the movement, pitching himself forward with god only knows what muscles and catapulting himself over Shiro with unexpectedly acrobatic grace.

Shiro laughs, delighted, twisting away from Keith when he tries to pull him off balance. "How did you even _do_ that?"

Keith doesn't answer, except by way of a tiny, pleased grin. Then they're closing again, exchanging a flurry of kicks and punches that leave no time for coherent thought or laughter, just the business of _yes, this_ and _now, there_ and the pleasure of moving against an opponent who matches him so well—pushes him so hard—for the simple satisfaction of the movement. It's exhilarating, something Shiro hadn't even realized he'd been wanting until he was in the middle of it.

It ends when Shiro underestimates the upper bounds of Keith's hidden strength and ends up getting pinned instead of being the one to do the pinning—Keith plants a knee at the small of his back, his hand between Shiro's shoulder blades and the other wrapped around Shiro's wrist as he twists Shiro's arm behind his back. 

Shiro laughs again, breathless, and taps out. Keith turns loose of him and is on his feet again in the same heartbeat, stretching a hand down to Shiro. Shiro takes the offer, expecting Keith to balance him as he gets up, but Keith hauls him to his feet instead. "Whoa!" Shiro has to brace himself with a hand against Keith's chest to keep himself from overbalancing. "You _have_ been holding out on me."

Keith lets go of his hand and steps back, running his hands through his hair and not quite looking at him. "It freaks people out when you're too strong to be human." He says it like it's simply a matter of fact, not his life and the secrets of his heritage and the way he watches everyone, trying to take his cues from their leads.

Shiro takes a step forward so he can lay his hand on Keith's shoulder; he waits until Keith sneaks a stealthy glance up at him. "Guess it's a good thing that I'm not people, isn't it?"

Keith snorts. "You always have been something else." He reaches up and covers Shiro's hand with his own. "That's why I figured you wouldn't mind seeing."

"The opposite of minding. That was great."

It is absolutely worth every last bruise he's just acquired just for the way Keith smiles, part pleased and part relieved. "That's good, I guess."

Shiro smiles and squeezes his shoulder. "Come on, it's getting late, we should get cleaned up and get some sleep, okay?"

Keith exhales. "Yeah, okay."

The nice thing about sparring barehanded is that there's nothing to tidy away; they head for their quarters in companionable silence, falling in step. 

Shiro really had meant it about hitting the showers and then going to bed, but all the same he's not surprised when they come to his door and Keith clears his throat. "Can I…?"

"Of course." Shiro palms the door open for Keith to precede him into his quarters, watching Keith's shoulders drop farther with each step. 

He really does hope it's not going to be as much work to persuade Keith that he really is a wanted—cherished—part of his life for the second time as it was the first. Maybe it'll be easier, now that the secret of Keith's heritage is out in the open. Shiro can hope, anyway.

Keith turns to meet him as the lights come up and the door slides shut behind him, rising up on the balls of his feet and sliding his hands up Shiro's chest as he tips his mouth up for a kiss, one that Shiro is more than happy enough to provide. He fits his hands to Keith's hips to pull him the rest of the way into his space, bending to meet Keith's mouth, which is the same as it's ever been, slightly chapped because Keith worries at his lips with his teeth when he's concentrating, but eager, always eager, for more and deeper. 

Shiro used to worry sometimes about how greedy he could be for Keith, for the slickness of their tongues and the tender, swollen curve of Keith's lips caught between his teeth, the way he can't help diving in for one more kiss—and just one more—but he's long since cast that worry aside. There are too many real, urgent things to spend his worry on. These days, desiring Keith as much as he does has become a welcome respite from his real problems.

It's easy to lose track of time in the movement of Keith's mouth against his, the way he tastes and the soft pleased sounds he makes, the way he's sized just right for Shiro to edge his thumbs under the hem of his shirt and stroke them over the crests of his hipbones, fitting them into the hollows as Keith shivers.

It's Keith whose impatience moves them, Keith who fits a hand between them to cup Shiro through his pants and bear down against him.

Shiro breaks away from Keith's mouth to voice his groan, deep with the flare of heat. " _Keith._ "

Keith squeezes, maybe to make a point or maybe just because he loves driving Shiro crazy. "Clothes," he says while the fireworks are still going off inside Shiro's skull. "They need to come off."

That sounds like an _excellent_ plan to Shiro, loath as he is to actually let go of Keith long enough to strip.

Needs must, and Keith makes the point moot by stepping back and reaching a hand back to yank his t-shirt over his head. Shiro follows his lead, unzipping his vest and casting it aside, only to be distracted by the way Keith has already gotten himself bare and is standing there in all his glory. He catches Shiro looking and ducks his head just a bit, watching Shiro with the edge of the smile that's only for him. "See something you like?"

"You know I do." He smiles as Keith ducks his head farther, mouth curling wider, and peels his own shirt off.

Keith hisses as he does; when Shiro gets clear of his shirt, Keith is staring at him—at his torso—as upset as Shiro's ever seen him. "Why didn't you say something?"

"About what?" Shiro looks down at himself and sees nothing remarkable. Keith is long since familiar with the mess of scars that map out his year of captivity. Even says he doesn't mind them, because he'd rather have Shiro with them than the other way around. 

Keith reaches out and lays his fingertips against a rosy patch of skin just above Shiro's hip. In another hour or so it's going to be a very respectable bruise. Shiro thinks it's from catching one of Keith's kicks the hard way. Keith swallows and looks up at him, guilt-stricken. "We were just supposed to be sparring. I didn't mean to _hurt_ you."

Oh. Shiro covers Keith's hand with his own, pressing it to his skin. "Don't. I can't remember the last time I had that much fun on the training deck."

Keith bites his lip, searching Shiro's face for some sign that he's, what, shading the truth for his benefit? As if Shiro would ever do that to him. He lets out a breath, only a little shaky. "What, you've forgotten the time you pinned me to the wall and fucked me already?"

"Punk." Shiro pulls him closer. "Okay, that's the second-most fun I remember having on the training deck. Definitely the most fun I've had with my clothes on."

God, he loves the sly little curl of Keith's smile. "I don't know, that time with the wall, you kept your clothes on then, too."

Shiro huffs at him and slides his hand down to smack Keith's bare ass. "Will you stop arguing with me and just let me tell you that I enjoyed being thrown around the training deck by my tiny adorable boyfriend?"

Keith grimaces. "Tiny _and_ adorable, really? Can't you let me have at least _some_ dignity?"

Shiro plants a kiss on Keith's forehead, mostly because he can. "You have plenty of dignity. Tiny, adorable dignity."

"I didn't hit you hard enough," Keith decides. "I'll fix that next time."

"Looking forward to it," Shiro promises him.

Keith peers up at him. "You really are, aren't you?" He sounds—looks—surprised. "You liked it."

"I said I did." Shiro grins at him. "If you play your cards right, maybe you'll be pinning me to the wall next time."

Keith blinks, slow, absorbing that. "Why wait until then?" He drops his hands to Shiro's fly and undoes it. "These need to be off, now."

Patience has its rewards, sure, but there's something to be said for impatience too. Shiro kicks his way out of his boots and pants with Keith's nimble assistance and lets Keith pull him deeper into the room, close enough to swipe the tube of slippery gel cached at the food of the bunk before he turns them and Shiro feels the wall, cool against his back. Or maybe it only feels cool because of how hot Keith has him running. Keith presses against him, raising himself up enough to kiss him again. Shiro hums into his mouth, parting his lips for the insistent stroke of Keith's tongue, at least until Keith draws away, lowering himself from his toes at the same time he cups a hand around Shiro's ass and slides it down the back of his thigh.

Shiro pulls his knee up and hooks it around Keith's waist, using the subtle curve of Keith's ass to keep his heel from slipping down. Keith reaches under him, fingers cool and slick, and Shiro forgets to worry about the details as all his attention focuses down to the slow, intimate movement of Keith's fingers against him, _inside_ him, an aching sort of burn that ripens into heat as Keith sinks his fingers home, curved just right to hit his prostate. 

Shiro leans his head back, groaning as Keith draws his fingers back just a bit and then slides them home again with pinpoint precision. The sensation ricochets up his spine and steals his breath with how good it is, how merciless Keith can be when he wants to be (he always wants to be when they're in bed, when he's giving Shiro pleasure). Keith presses his mouth to Shiro's chest, tracing his lips and tongue across the mess of it as he circles his fingertips against Shiro's prostate; when he reaches Shiro's nipple, he catches it between his teeth and _tugs_.

Shiro shouts, back coming off the wall as he arches between the two sensations, the sting of Keith's teeth and the electric pressure of his fingers, _Jesus_ , he's going to come just like this—

Keith lets go and strokes the flat of his tongue over Shiro's nipple at the same time he eases his fingers back, back to the point where they're barely holding Shiro open. Shiro moans—may even whine—at the drop-off. "Keith."

"You're going to come on my cock," Keith informs him. He reflects on it as he slides his fingers free. "The first time. The second, too, probably." He spills more of the lube over his fingers and then runs them over his cock, expression going distant and blank with pleasure as he does. 

"What about the third time?" Shiro can't help but ask. Keith is merciless, sure, but the human body does have its limits.

On the other hand, Keith's body isn't strictly human, is it?

Keith's smile is white and sharp. "After that, we'll see." He gets his slick hand under the leg Shiro already has wrapped around him, bracing him, and runs the other down the back of the leg Shiro still has planted against the deck.

Shiro _knows_ that Keith is strong, stronger than he's ever let on before, and it still shocks him when Keith lifts him, shoulders and biceps rippling smoothly, and holds him pinned against the wall. Shiro groans, wrapping his legs around Keith's waist as heat knots at the pit of his stomach. "God, Keith…"

"Mm." Keith's smile stretches wider, and then he's lowering Shiro, pulling him down on his cock in a single steady, controlled movement. 

Shiro drops his head back against the wall, panting against the fullness of the stretch, at how effortlessly Keith is handling him. He winds his arms around Keith's shoulders and shudders as Keith comes to rest, buried to the hilt. " _God_."

Keith hums to him again, the sound deep in his throat, and that's the only warning Shiro gets before Keith adjusts his grip on Shiro and snaps his hips forward, hard and fast enough that Shiro sees stars. He shouts again, clutching Keith's shoulders as raw pleasure punches through him with no time to recede before Keith does it again—and again—and one more time—

He's not left hanging this time, falls over the edge on a strangled shout at Keith sinks into him, body spasming as pleasure rakes its way over every nerve Shiro possesses.

He feels Keith's growl more than he hears it, a subsonic rumble of satisfaction as Shiro arches between him and the wall, shaking with the force of his pleasure. Keith holds him steady, never faltering as he fucks Shiro through it, sharp jabbing thrusts that draw it out, keep him from being quite able to come back down from the edge—

Until Shiro gasps something, a plea or Keith's name, and Keith sinks into him and holds there.

Shiro slumps, breathing hard, every part of him trembling and exquisitely sensitive and aware of the way Keith still has him stretched open, filled up, hands just as steady on him as they were to start, though Keith's skin gleams with sweat and his hair clings to his temples in a damp tangle. Shiro moans—Keith has been holding out on _so much_ —

Keith's laugh, husky and rueful, jolts through him the same way the realization does. "Not any more," he says. "You get it all now, I promise."

The only thing Shiro can do with that is fold himself over so he can kiss Keith, pouring himself into the sloppy slide of his lips against Keith's and trusting that Keith will understand all the things he doesn't know how to say. Maybe he does; he sucks Shiro's tongue into his mouth and rolls his hips against Shiro, the drag and push of it languorous and unceasing, never quite coming to a rest inside Shiro or drawing completely free of him either. 

Shiro sinks his fingers into Keith's hair and groans, dizzy with the sensation lapping through him, as sweet as the sounds Keith makes every time he sinks home, open and reverent against Shiro's mouth. 

It's so much, too much for anyone to deserve, let alone him of all people, and so Shiro holds onto it with both hands, greedy for everything he can get as the sensation twists through him, doubling and redoubling on itself until he doesn't know how he can bear it.

Then Keith reaches between them and clasps his fingers around Shiro, stroking him, coaxing him back over the edge. 

Shiro groans, open and breathless, tumbling headlong into the rush of pleasure that surges over him as he spills over Keith's fingers. Keith groans too, close enough that Shiro feels the tremor that rolls through him as he comes, too, though his grip on Shiro never falters.

Shiro slumps against him, dropping his forehead to Keith's shoulder and shutting his eyes against the half-light of his quarters—too bright by far. 

Keith takes his weight without complaint, breathing hard against Shiro's ear, before adjusting his hands under Shiro. Before Shiro can muster the wherewithal to wonder what he's doing, Keith edges back from the wall, one careful step at a time. He doesn't stop until he's got Shiro flat on his back in the bunk and is kneeling over him. 

Shiro has to clear his throat and wet his lips before he can speak. " _God_ , Keith."

A tiny, pleased smile kicks up the corners of Keith's mouth. "You liked that, huh?"

" _Liked_ isn't even close to the right word." Shiro pulls him down since there's no way he's boosting himself up to kiss the smile off Keith's mouth. "That was amazing."

Keith fumbles at a corner of the blanket and wipes up the worst of the mess before he makes himself comfortable against Shiro's chest. "I guess that's good."

"So good," Shiro says, utterly in earnest.

Keith hums and presses closer. After a moment, he says, "Thanks."

Shiro lifts a hand so he can pet Keith's hair. "My tiny, adorable, _incredibly strong_ boyfriend."

Keith sighs. "I guess that's an improvement. Sort of."

Shiro turns his head and presses his lips against Keith's temple. "Go to sleep, and in the morning you can show me what else you can do, okay?"

"Yeah, okay, I will," Keith says, and he does.

**Author's Note:**

> Comments and kudos are always lovely!


End file.
